SVC for load balancing and maintaining of power quality in an island grid feeding a nickel smelter

Societe Le Nickel (SLN) is a nickel plant situated in New Caledonia. The plant operates a nickel smelter based on submerged arc reduction furnaces. The submerged arc furnaces introduce considerable unbalance in the load on the three-phase power supply. They are also a source of harmonics. At the same time, local alternators have limited endurance to phase unbalance, lest they suffer added heating and consequent derating of life span. To limit the impact of phase unbalance as well as reduce the amount of harmonic distortion entering into the power grid, a Static Var Compensator (SVC) has been installed in the smelter. SVC for mitigation of the impact of submerged-arc reduction furnaces on power grids is a novel direction in SVC applications and represents a widening of the scope and usefulness of SVC. Furthermore, the SVC in operation in the SLN plant is directly connected to the 63 kV grid, an important step forward in SVC technology, as far as voltage handling capability is concerned. The paper is treating these matters, as well as elaborating on the SVC design. Some operational experience and benefits of the SVC installation are included, as well.